Just in case you are an astronaut and need something to worry about, according to NASA there are 18,000 pieces of space junk the size of a basketball or larger right now orbiting the earth. That’s 18,000 chances to slam into the International Space Station (ISS), bump into a U.S. Space Shuttle, or plow into any of a number of satellites in low Earth orbit. Twice the ISS has had to be moved to avoid potential collisions and one other time when it couldn’t be moved the crew huddled in their Soyuz taxicab for danger to pass, with one such near-miss taking place just last week, which is what inspired this column.